Furnace chunk breaker



April 18, 1961 F. J. BORON FURNACE CHUNK BREAKER 2 Sheets-Sheet 1INVENTOR. FRANK J. BORON Filed April 11, 1958 ATTORNEYS April 18, 1961F. J. BORON FURNACE CHUNK BREAKER 2 Sheets-Sheet 2 Filed April 11, 1958INVENTOR. FRANK J. BORON ATTORNEYS FURNACE CHUNK BREAKER Frank J. Boron,Elyria, Ohio, assignor to American Brake Shoe Company, New York, N.Y., acorporation of Delaware 7 Filed Apr. 11, 1958, Ser. No. 728,010

9 Claims. (Cl. 241- 67) This invention relates to the construction ofequipment for a furnace of the kind used to fire ore-bearing material orthe like incidental to the processing of'such material, and the presentinvention is concerned in particular with the construction ofoscillating shafts that are mounted adjacent the furnace and which areto be provided with discs for breaking up the material processed in andemitting from the furnace.

In one form of furnace installation used to process ore-bearing materialand the like, the material which is fired in the furnace is funneled outthe bottom of the furnace, and spaced parallel rotating shafts composedof steel are interposed to assist in breaking up the fired materialemitting from the furnace so that the material is subdivided prior tofalling onto transfer belts. Such shafts are provided with so-calledbreaker discs composed of steel and secured thereto, and the breakerdiscs are formed with teeth about the outer peripheries thereof whichassist in breaking up the burden much in the manner of oscillatablefurnace grates. Heretofore, the discs have been joined directly to theshafts, that is, there is a continuous line contact between the adjacentsurfaces of the shafts and the discs, and because of the hightemperatures encountered the shafts are arranged for water cooling bydirecting cooling water through hollow internal areas formed in theshafts which prolongs the life of the shaft and the discs.

For the most part, it is the breaker discs which accomplish the work bycrushing the material fed to and emitting from the bottom of thefurnace. In more recent years, however, higher and higher temperaturesare being resorted to in such furnaces, and it is now recognized that inorder for the, breaker discs to have an appreciable life it is necessaryto compose the, breaker discs of expensive heat-resistant alloy. On theother hand, it is desirable to construct the-supporting shafts for thebreaker discs ,of steel having good heat conductivity, but steel ofcourse hasa quite different coeflicient of thermal expansion compared toa heatresistant alloy such as an alloy composed of 10 to 30% chromium,to 30% nickel, 0.1 to 20% manganese, 0.1 to 0.8% carbon, remaindersubstantially all iron with a 3% maximum tolerance in silicon. Thisdifference in thermal coefiicient characteristics coupled with thewatercooled steel shaft introduces a serious problem insofar as thethermal stressing of the alloy discs is concerned, and itis the primaryobject of the present invention to enable chunk breaker discs composedof a heat-resistant alloy such as the foregoing to be secured to awatercooled steel shaft under such circumstances that the likelihood ofsevere or undue thermal stressing of the alloy discs is greatly reduced.

Thus, in contra-distinction to prior and existent arrangements whereinthe breaker discs are secured to the shafts either by a continuous linecontact in the nature of a press fit or continuous 360 welds, alloybreaker discs in accordance with the present invention: are

United States Patent O mounted on the shafts with as little contact aspossible between the adjacent surfaces of the shafts and the discs. Thisis accomplished under the present invention by specific modes ofestablishing a spaced union between the discs and the shaft, and theseare exemplified in all instances by first of all cavitating or hollowingthe inner diameter of the discs to afford a U-shaped section defined byspaced apart thin arcuate rims thereby reducing the area of the discswhich are immediately adjacent or opposite the outer diameter of theshaft on which the discs are mounted. In order to establish spacingbetween the narrow rims of the discs andthe adjacent surfaces of theshaft, the rims of the disc are of larger inside diameter than theoutside diameter of the shaft, and a drive connection of very limitedsurface contact is established between the discs and the shaft inseveral different ways as will be described hereinafter. The discs,extend about the shaft for 360, but advantageously each disc can becomposed of a plurality of segments with spacing between the adjacentends of the segments allowing for free contraction and expansion of thediscs relative to the shaft in a circumferential sense. 7

Other and further objects of the present invention will be apparent fromthe following description and claims and are illustrated in theaccompanying drawings which, ,by way of illustration, show preferredembodiments of the present invention and the principles thereof and whatI now consider to be the best mode in which I have contemplated applyingthose principles. Other embodiments of the invention embodying the sameor equivalent principles may be used and structural changes may be madeas desired by those skilled in theart without departing from the presentinvention and the purview of the appended claims. I

In the drawings:

Fig. 1 is a sectional view of a hopper to be mounted beneath a furnaceof the kind mentioned above, and showing end views of a plurality ofshafts having breaker discs thereon constructed and arranged inaccordance with the present invention;

Figs. 2 and 3 are side views of the shafts shown in end elevation inFig. 1 and further illustrating constructions .contemplated by thepresent invention;

Fig. 4 is a plan view of one form of breaker disc constructed inaccordance with the present invention;

Fig. 5 is a sectional view taken substantially on the lineS-S of Fig. 4;

, Fig. 6 is a view taken substantially on the line 66 te en Fig. 7 is asectional viewtaken substantially on the line 7--7 of Fig. 6; Fig. 8 isa plan view of a modified form of breaker disc constructed in accordancewith the present invention;

Fig. 9 is a sectional view taken substantially on the line 99 of Fig. 8;

Fig. 10 is a sectional view taken on the line 1010 of Fig. 11;

Fig. 11 is a sectional view taken substantially on the line 11-11 ofFig. 10;

Fig. 12 is a plan view of another modified form of breaker discconstructed in accordance with the present invention; i I

Fig. '13 is a sectional view taken substantially on the line 13-13 ofFig. 12;

' ore material and the like charged in the furnace the'flow 'fThebreaker discs .D are advantageously arranged ;in rliiferent patterns onthe "shafts to account for a .predematerial from the furnace (notshown)- being conveniently indicated by legend. It will be observed thata pair of hoppers H1 and EH2 are in a lower position in the area A andare-secured to a relatively large mount ing 4515:; 3( the arrangementbeing such that the lower discharge end of the hoppers are disposed'tofunnel and discharge the material .passing through the thoppers -H1'tilTeriefoii oh tol'such conveyors -or the like, ;a plurality .of

ers

is s,'-,genera11y indicated at D in Fig. l -and to be demined, ingreater 'de'tailfhereinafter, are ;:indiv idually own) and'eachhliaftfas shown tinlFigs. 2 tand-.3, ;is o withanaidaligfoo've G inwhich fits a:k ey.ca rried' hytheidrivemean's for rotating the shafts-S.The discs D 'a1f'efpfrovidedwith'lteethiT, Fig. 1 as will be described,

' this mannemne rotating discs tend to crushand i rea'kilp 'largefchunksor the iii-flowing material ;-movingfromthe' furnace in the direction'of thefhoppers H1 and tennind op,timum' cru'shiiig or breaking action.:Thus, referring 'tofFig's. 2 andi3, two off'the shafts S, indicatedeff-S2 ands}, respectively, are so; constructed fthatthe 52 carries fourdiscsjD 'whereas' meshes S3 Icarshafts S towhichtheyarejallocate V lnfu'rnaces -of' the'kind'under consideration, relatively hightemperatures are developed such tha't'the inflow of 7 7 material'in thearea A causes severe overheating of the shafts =8 and -then discs D. 'Inorder to'piolong the life oflthe shafts 8, it has previously beenproposed 'to 'form "the 'shafts of 'a hollow construction to enablecooling 3'! the hoppers is properly broken up prior to deposit' in ed to'the fshaft's spacedrelation soas -to;rotate' herewith. V The shaftsS-aresupported byv bearings (not 'fc hnnk breakersha'fts S are arrangedin two horizontal dve'the'disc'harge endsof the hoppers, and-break- '15circumferentialiexpansiontandwontraction; and the empresent inventionare primarily distin- 7 V om't'he'iotherbn'theihasis o f't'heiparticularmanner lI'l'WhlCh the disc'sc'an be joinedto the shafts forrotationtherewith. 7 1 a a One enhodirient ofza lcfiisflfer or chunk.b'reaker disc constructed in accordance with thepresent invention isillustrated in Figs. Z 't'o Tinclusive'l "Thus, the disc 25, Figs. 4 and5, is in the form of an'annular one-piece part cast from the alloyspecified above or one closely lakin thereto. :The disci 25-has asolidcircumferential or annulai--=outer wall .-26"from whicheprojectauplurality of integrally fcast,;teeth orgilugs 27 ;.of solidconstruction breaking '-el e:ment'swhich account for thedesireclgrindwater to be directed into the interior thereof as indicated bylegend in Figs. 2 and 3.

In accordance with the presntinvention, the discs D,

all 'consist "of "a "heat resistant alloy of arelativel'y expensivenature in comparison to ordinary ferrous metal :alloys. Thus, discs of"the of thef'ollowing:

C ---0.10-0-.80 V Ni 5-30 Cr -'30 Mn Si =3%-max. Fe h e a --Balance 7The alloy used for the discs'D'has(quite-different therpresent inventionmay be cast mal;.characteristics in comparison to stainless steel Fusedfor the shafts S which, as explained above, are tobe water-cooled. Henceit 7 becomes important, especially in, view of the initial cost of thealloy discs D, to prolong their life andto assure thatthere'will be no"cracking or warpage due to the association ofthe dis'cs-D with :thewater-cooled-shafts S. In accordance with thep'resent invention, thediscs D are configured andarran'ged to have as little peripheral contactas possible with the 6 tween the shafts S and the discs] D -to cause-thediscs .D to rotate with the shafts-S. Three-diflerent'iembodi- {annularspaced-apart rims th'ere'by deducing" in 'the sfirst th'liiz'efthe.possible ereaeontaet between itherdiscs ED aiid'the relat'e'dshaft s.Additionally, the internal di-l throughout, the"tee'thr27 in cooperationwith iiketeeth {OH =an :op'po'site shaft as S representing the grindingor "ing or breaking-action -on the -material flowing from the 5furnace'into the'area A'and downward past the shafts ;as -S. 'I;{he=disc-iscast to -'havea pair of spaced-apart {side rwalls or flanges ;30and-31 integral with and projecting-radially :inwardly from the outercircumferential wall26 ,;and these flanges terminate in fiatannular-rims EItlRandSlR which definethe inside diameter of each*disc-as 25.7 'ii' he "distance separating the outer surfaces .of thesidewallsiil and -3 1 is;nogreater than the maxi-. mm width each tooth'2 7-,-ibut the side walls and their rims .3llR- and are of narroweraxial *width ft'haniare thefteeth 27. {In fact the combined width-orTthikness foil the .walls .30 and-31 is p less than that of a "tooth 27and this accounts; forthe hollow nature of the Zdisc"2 5. 'a'hout itsinside diameter. 7 I

' As shoWnT'in wFig.i5 itheurimsof' the disc 25am to concentrically'sufrbund :the shaftfS but: are to be spaced Tslight'ly therefrombylhavingthe rims of greater diameter ,than the outside fliameter of therelated shaft S. In

order that each disc asf25 will rotate with the shaft S,

- jinitiimize the.transfertoflheatgbetween the .disc and the shafts. w Ia H njassen'ibling the 'disesIZS voiithe shaft-S, shown'in 4 i 25v willbe turned until'the'keyreceiving' 'recesssdftherein are aligned 'withthe keys 35 on'the shaft sywhereupon each disc is slipped into fplace bybeiiigfnoved' axially'along the shaft -S until itsflzey-receivingjopen'ings,are related to those keys 35 whichdefinethe'locatidn dflthe.partictilardiselS on theshaft S. :AsshowninFig. 7, t'he 'keysSS are-securedin place by arguments, 1 i

,j'In o'rder'th'at each disc will be properly held in its {selected jaiialjpdsition on: the shaft S, retainer lugs 40 a gndf t'lfl-iigj, arewelded to the outer end surfaces of :the keys 35 are: the related discshave been-assembled in propenp'ositio'n. :-lugs'40 and 41 are to bedisposed opposite solid surfacespatjthe 'sides ":of the disc. Asshbwnparticularly inF-ig; -7, itisrpreferable to have .spacing betweenthe 1 opposedssurfaces fof such lu'gs I and theeside -walls 30":and31iof=each disc 25, again contributing tofthe Eattainmentof c'as:littleeontact as possible be- :tween'vthediscss25i and parts directly'in 'c'ont'act with the 15 shaft s.

. Another form of the present invention is illustrated in breaker discof annular form is-assembled from four segments 50-1, 50-2, 50-3, and50-4, the relationship being such that when the segments are arrangedend-toend to complete a 360 circle, the adjacent ends thereof are spacedslightly from one another as indicated at SP, and such spacing allowsfor circumferential expansion of the disc assembly 50 relative to theshaft S, Fig. 11, on which such discs are assembled in complemental seg-'mental form. Each disc. segment, illustrated in Fig. 8,

is formed with a pair of solid teeth 53 and the inside diameter of eachsegment is hollowed to provide a spaced lpair of arcuate side walls orflanges 55 and 56 having rims 55R and 56R which represent the insidediameter of the assembled disc 50. As in the foregoing embodiment theside walls and their rims 55R and 56R are each of narrower axialdimension in comparison to the teeth 53, and in fact this istrue of thecombined dimension of the rims accounting for the hollow internalconstruction to reduce the possible area contact between th disc 50 andits shaft S.

As in the instance of the disc 25, the disc 50- composed of the severalsegments mentioned above is to be so arranged on the shaft S as to havespacing between the outside diameter of the shaft S and the innersurfaces of the flanges 55 and 56.

In the instance of the disc 25, it will be realized tha the disc 25 hassome play on the shaft S and that in the actual construction each disc25 will have at least a point of contact with the shaft S. This contactis of no moment, however, insofar as the essential feature of thepresent invention is concerned which resides in having as little contactas possible between the discs and their shafts. Since, however, the disc50 is not of one-piece construction, a shim of cardboard 60 or the likeis fitted abo'ut'that portion of the shaft S where a disc 50 is to 'bemounted. Theindividual disc segments illustrated in Fig. 8 are thenlocated one-by-one on the shim with the inner rim surfaces of theflanged side walls 55 and 56 in contact with the shim as shown in Figs.10 and 11, whereupon spaced weldments of spot form, as shown in Fig. 10,are laid down to unite each segment directly to the shaft S as shown inFig. 10 for rotation therewith. Because the weldments do establish adirect contact between the disc as 50 and its shaft S, such weldmentsshould be held to the minimum necessary to procure a firm andsustainable union.

.Still a third form of the present invention is illustrated in Figs. 12to 15, inclusive. This particular form of the invention in realityembodies some of the features or both of the two embodiments describedabove. Thus, the chunk breaker disc 70, shown in Fig. 12, is composed ofindividual segments, but instead of welding these segments directly tothe shaft S in the manner described above in connection with Figs. 10and 11, spacer bars 75, Figs. 14 and 15, are first interposed betweenthe inside diameter of the disc 70, represented by the disc rims 76R and77R, and the outside diameter of the shaft S on which the discs 70 aremounted to thereby account for a greater degree of radial spacingbetween the rims of the discs 70 and the related shaft S than isafforded by the modified form of the invention illustrated in Figs. 8 to11.

Assuming that the teeth on the various different forms of breaker discsunder the present invention are all to lie on a common circle, the discat 70 can in factbe viewed as one wherein the radial dimensions of theside Walls 76 and 77 thereof are shortened in comparison to the sidewalls 55 and 56 of the disc 50. Thus, the side walls 76 and 77 of thedisc 70 are of shorter radial dimension than the side walls 55 and 56 ofthe disc 50, and hence the inner diameter of the disc 70 defined by theradial inner surfaces, 76R and 77R of the side walls 76 and 77 arespaced radially outwardly of the outer diameter of the shaft S, Figs. 14and 15, a greater distance than the corresponding spacing in Figs. 10and 11. In the greater space thus established between the outsidediameter of the shaft S and the inside diameter of the disc 70, aplurality of elongated rectangular steel spacer bars 75 are Welded at Wto the outer diameter of the shaft S in spaced circumferential relation,and the dimension of the parts is such that the internal diameter of therims afforded by the axially narrowed side walls of the disc 70 are tobe radially spaced at ST from the outer surfaces of the spacer bar 75.This spacing can be established by using shims on the outer radialsurfaces of the spacer bars in the manner described above.

As in the instance of the disc 50, each disc 70 is constructed from foursegments, each having a pair of teeth 79 which are hollow insidediameter of each segment. The segments comprising the disc 70 aredimensioned to establish spacing SP2 between the adjacent ends thereofwhen the segments are properly assembled in a circle,

and as each segment is assembled about the related shaft S weldments W2are deposited between the ends of the spacer bars 75 and the side wallsof the segments to secure the latter to the spacer bars for rotationwith the related shaft S.

It will be seen from the foregoing that in accordance with the presentinvention chunk breaker discs, cast from the heat-resistant alloyspecified above or one closely akin thereof, are formed to embody spacedarcuate rims of less axial thickness than the thickness of the arcuateouter wall of the discand the teeth which project from the outer wall.Additionally, the rims of the discs are of larger inside diameter thanthe outside diameter of the steel shaft on which the discs are to bemounted, and this arrangement and configuration accounts in the firstinstance for as little contact as possible between the opposed surfacesof the discs and mounting surface of the shaft. In this way, the chancesor likelihood of thermal warpage or cracking of the expensiveheat-resistant discs, due to the difference in thermal co-efi'icientsbetween the steel shaft and the discs, is reduced thereby minimizingmaintenance problems. It is of course necessary to provide some sort ofunion between the shaft and the discs in order that the discs. willrotate with the shaft, and such union in accordance with the presentinvention is also of such order as to produce as little contact aspossible between the discs and parts in direct contact with the shaft.

Hence, while I have illustrated and described preferred embodiments ofmy invention it is to be understood that these are capable of variationand modification, and I therefore do not wish to be limited to theprecise details set forth, but desire to avail myself of such changesand alterations as fall within the purview of the following claims.

I claim:

1. In a chunk breaker to be installed adjacent a furnace for breaking uphot chunks of material discharged from the furnace, a cylindricalsupporting shaft adapted to be rotated and cooled internally by means ofa fluid cooling stream, said shaft being composed of ferrous materialhaving a given coefficient of thermal expansion, and a breaker discmounted on said shaft and extending circumferentially thereabout forrotation therewith, said disc being composed of a heat-resistant ferrousmetal alloy having a coefficient of thermal expansion difierent fromthat of said shaft, said disc having spaced teeth of uniform dimensionformed on the outer periphery thereof and having an arcuate innerperipheral rim of narrower axial dimension than said teeth and ofgreater diameter than the outside diameter of said shaft, and meanscontacting the outer surface of the shaft at circumferentially spacedpoints and securing the disc to the outer periphery of said shaft withspacing between the arcuate inner surface of said rim and the outersurface of said shaft.

2. In a chunk breaker to be installed adjacent a fur- 7 having; a pairof js'p'aced a'part innerfp e is A e nac'ef'for bre'aldngriup hot chunksof materialiliseharged fron'1 the furnjace,- a supporting shaftalaptedl'O jbe' l'O- jtatea and cooled i'internally by mean ot a fluiq eeplingstream; said shaft Bein c'o'm'pose'd of ferrous mate-rial :hreakerdiscmounted Unsaid shaftffor -rotation therewith, said disc bein'geomp'os'edof a heat-resistantfer rous "metal alloy having a cOefiicient-of thermalexpansion diffferentf'from that of said shaft,"s'aid'dZschaying spaced:feethfo'rmed'on the outer periphery thereofland having [aninnerperipheralarcuate rim of n'arrower axialfdim'ensio'n than 'saidteeth, 'andhie'ans contacting the outer'sur- V face'of'the shaft atacir'curnfe'rentially spaced points-and ,s e'curingthedisc to theohterlperiphery of 'saildSh'aft with V spacing between the arcuate innersurface of said rim aiifdftheouter surface of said shaft. 7 V V a 3."-In chunk breaker to betnstalleh ,adjaeentatur- "nice 'for breaking uphot l'cliuriks, of ematerial-di'seharged iirointhe furnace, vacylindrical supportingishaftfadajite'd to be rotated and {cooledinternally by means .6 poolin stream, jsaid shaft being .composedlloflferrous ,mat'er-ialha'ving a given,coefiieientof'thermalex ansion,

and a breaker disc mountedon' said s'hzifti'for rotation therewith, saiddisc being composed of a heatr'esista'nt ferrous, metjali'alloy having a"coefficient "of th e'r'rnal ex- ,Iiansion' different from that ofsaidfsha' fhf said discfhaying jsp'aced teeth formed on the outer'pe'rip'hery "thereof, and i phe'ral .arcuate "rims each of narrower'axi'al dimension'j 'shafLand means contacting the outerjsu'r'faceoftheshaft fiat circumferentially spaced .p'oin'ts and secufrin'gjthe discit'othe Outer periphery of said sha'ft'with spacing between the arcuateinnersurfa'ce ofsaid rim and the -oute'r 'surface of saidsh'aft. U V V4.7A chunk 'breaker according to claimj'3-where'in the 'disc isweldedjat s'pacedjpoin'ts itotheou'ter surface of V I an said teeth; andof ia'r'g'er diameterthan the outer'l iiam'eterbf said 7 7; Ag-chunkbreaker accordinglto. iwherein :spac'er -barsesecured tojhe outersurface: of 4 the shaft "are interposed between the rims oi the ,disdandthe outer surface of the shaft;

' j k disc d'a ted tohe m'ountetdjon a'fshaft to afiord 1a :jchunk'breaker shaft and cqmp'rjising.anjarcuatej outer iwall haying apluralityof radially projecting 'teethformefl thereon "in "a single -1 oW and 'incircumferential "spaced relation, said" teeth each having a givenajlthickness and-a given radialfprojecting 'dimensi'on, "'an'd3said discbeing formed withfspaced substantially parallel arcu'at'e side xwalls'afi ordingspaced ar cu'at'e inner rims which are concentric to saidar'cua'te outenwa'llgsaid rims each being pf less axial thicknessthanfthe; individual axial fihickness *ojtlsaid'teeth." 1 a I lj '9.;Ina chunksbrealcerfto be installed'adja'cenfa'furnace for breaking up hotchunks o'f rnater'ial emitting "from the furnace, a supporting shaftadapted tofbe rotatedand cooled internally bymjeans of "a 'fiuidqco'oling streamgand a plurality of breaker discs mounted thereonffor-rotation therewith, said 'discs e'ach having spaced teeth iorrned'in but a single circumferential row aboutfth'e :outer periphery -thereoffandeach having an jinnerfperiph- \erai rirnfoff narrower axial:dim'ension than fsaid'teeth, and-'means securing ea'ch disctoi thequter periphery "of "said shaft to :provide heafibarrier sp'ac'in'g be'tw'een the arcuate inner surface of each rim and the outer surface ofsaid shaftfsaid securingnieans contacting thje 'outer s'urfa'ce of theshaft discontinuously" atfwidely spaced points circurnferentiallyabout'the outer surface of; said sha'f'tand contacting e'ach' of said -'discs'fdiscontinuously i t "atW dely" c i ts-

